Video cassette recorders (VCR's) and combination camera-recorders (cam-corders) have been proposed that provide a relatively wideband luminance signal response (e.g., 5 MHz) and which include an output connector (commonly called an "S-terminal") that provides separated luminance and chrominance output signals. This new video interconnection standard is commonly known as the "SVHS" video format which stands for "super VHS". An advantage of this new (non-composite) video inter-connection format is that one may apply the separated luminance and chrominance signal to the display processing circuits of a television receiver directly without going through the receiver's internal luminance-chrominance signal separation filter (e.g., a comb filter). Advantageously, the SVHS video signal format eliminates interference effects such as cross-color and cross-luminance which otherwise could occur if the luminance and chrominance signals were to be combined as a composite video signal for application to the receiver.
Television receivers suitable for processing and displaying video signals of either composite form or of a separated luminance-chrominance signal format are known. An example is shown and described in UK Patent Application GB 2, 134, 743 A of Tanaka published Aug. 15, 1984 and entitled COLOR DISPLAY SYSTEM. In this system video input signals of composite type are applied to a comb filter for separation into comb-filtered luminance and chrominance components which are applied by means of respective switches to corresponding luminance and chrominance input of a display processing unit. The system includes a pair of input terminals for receiving respective ones of the luminance and chrominance components of a non-composite video input signal. For displaying signals of this format the switches are changed over to disconnect the comb filter from the display processor and connect the input terminals of the non-composite signal source to respective ones of the luminance and chrominance input terminals of the display processor.
Another example of a color television receiver having provisions for displaying signal of both composite and non-composite format is the "RCA" brand receiver employing the chassis type number CTC-159 manufactured and sold by Thomson Consumer Electronics, Inc., of Indianapolis, Ind. In this receiver the comb filter includes emitter follower output stages for applying the comb filtered luminance and chrominance signal to the display processor. The luminance and chrominance components of the non-composite (S-VHS) input signal are applied to respective output of the comb filter by means of respective switched amplifiers. The amplifiers are switched OFF to enable display of a composite video signal applied to the input of the comb filter. To display the S-VHS signal the amplifiers are switched ON thereby reverse biasing the emitter follower output transistors of the comb filter and coupling the amplified luminance and chrominance component of the S-VHS input signal to respective inputs of the display processor. Advantageously, this technique of selecting signals for display provides amplification as well as switching as compared with the system of Tanaka described above which only provides switching of the composite and non-composite signals. A further feature of this receiver is that a multi-pole input switch is provided for selecting one of a plurality of composite video input signals for application to the input of the comb filter and this switch is coupled to the comb filter by means of an amplifier whereby each composite video signal that is selected for display is subjected to amplification by the amplifier preceding g the comb filter and the S-VHS luminance and chrominance components are separately amplified by respective ones of the two switched amplifiers connected to the comb filter output terminals.